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DNA-barcoding has recently attracted considerable attention due to its potential utility in aiding in species identification and discovery through the use of a short standardized sequence of mitochondrial DNA. Nevertheless, despite the fact that this technology has been proven a useful tool in several animal taxa, it also demonstrated limitations that may hinder correct application. Thus, its validity needs to be empirically evaluated in each taxonomic category before forward implementation. As the use of DNA barcoding within Palaemonidae may be of special interest, given its great interspecific morphological conservatism associated with considerable intraspecific morphological variation, we analyze here the potential of this technology in distinguishing and recovering some taxonomic boundaries within this family. We asked whether two GenBank-retrieved sets of COI sequences encompassing the conventional Barcode and Jerry-Pat regions possess the desired properties of reciprocal monophyly among species, and existence of a barcoding gap between intra- and interspecific variations, after performing a careful analysis of numt (nuclear mitochondrial DNA) contamination. These analyses revealed nine non-monophyletic species, with some cases of divergent intraspecific sequences, contrasted with interspecific similarity attained in others. Moreover, we were unable to identify any barcoding gap between intraspecific and interspecific divergences within Palaemonidae, although a threshold of 0.18 substitutions per site would differentiate intraspecific and congeneric divergences in 95% of the cases for the barcoding region. A fraction of the overlap could be certainly attributed to artifacts related to poor taxonomy, but even from this perspective DNA barcoding studies may help to uncover previously disregarded taxonomic and evolutionary issues.

ABSTRACT. Species with a broad distribution rarely have the same genetic make-up throughout their entire range. In some cases, they may constitute a cryptic complex consisting of a few species, each with a narrow distribution, instead of a single-, widely distributed species. These differences can have profound impacts for biodiversity conservation planning. The genetic differentiation of four populations of Aegla longirostri, a freshwater crab found in two geographically isolated basins in Rio Grande do Sul State, Brazil, was investigated by analyzing pentanucleotide multi-loci microsatellites in a heteroduplex assay. Although no morphological differences were evident, we found significant genetic differentiation among the four populations, based on F ST values and clustering analysis. This high level of differentiation may be indicative of cryptic species in these populations. If this hypothesis is correct, then the species occurring in the Ibicuí-Mirim ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 10 (4): 4133-4146 (2011) M.L. River, at the southern limit of the Atlantic Rain Forest, would be under threat, considering its very restricted distribution.

Genetic divergences among populations of Aegla longirostri suggest that this group may be formed by cryptic species. In this study, we analysed the carapace shape of six populations of A. longirostri from southern Brazil, using a geometric morphometric approach, to better elucidate the species' systematics. Our results were congruent with the genetic data, meaning that genetically differentiated populations were also morphogeometrically differentiated. The geometric morphometric descriptors showed significant differences in carapace shape among all populations. Geographical distance and isolation may be affecting the gene flow between populations, leading to divergence in both genetic and morphometric traits. Our data indicate the possible existence of cryptic species within A. longirostri, or an incomplete process of speciation. Geometric morphometric methods were efficient in differentiating among populations that do not show divergence in diagnostic characters.

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-Aeglidae are anomuran freshwater "crabs" found only in southern South America. In Brazil, the greatest species diversity occurs in hydrographic basins of the state of Rio Grande do Sul. Two new species, Aegla georginae and Aegla ludwigi, are described from the Ibicuí and Ijuí Rivers, respectively (Uruguay River Basin). The new taxa can be distinguished from other Aegla species based on both morphological and molecular characters. The two new species have a very restricted distribution and are categorized as endangered (A. georginae) and critically endangered (A. ludwigi) using IUCN Red List criteria. We also summarize and present new records of the Aegla species occurring in the Uruguay River Basin.

1. Although freshwater ecosystems contain high biodiversity and provide valuable ecosystem services, they are severely threatened worldwide. Many broad-scale approaches to conserve freshwater environments have been proposed, but as headwaters tend to host higher levels of biodiversity, identifying priority areas for conservation at a local scale is essential.2. An integrative three-step framework is proposed to recognize such areas, using anomuran crabs of the family Aeglidae as biodiversity indicator taxa, within four freshwater ecoregions in South America. First, the knowledge on the distribution of species occurring within the study area was updated and the species conservation status assessed. Second, species distribution modelling was used to identify areas of high richness and endemism. Third, these areas were compared with the existing protected area network, in addition to land-use and urban information, to indicate priority areas for conservation within four freshwater ecoregions (Laguna dos Patos, Upper Uruguay, Lower Uruguay, Tramandaí and Mampituba) studied at a local scale.3. Analysis of the distribution of species of the genus Aegla showed that the present protected area network poorly covers freshwater habitats within the study region.Three priority areas for conservation were identified, with high levels of endemism and richness of aeglid species. These areas are mainly located close to current protected areas, and we suggest, therefore, that the enlargement of some protected areas, through the establishment of corridors, would better protect several species with distributions restricted to headwaters, such as macroinvertebrates and fishes, some of which are threatened with extinction.